THE USE OF ULTRASONIC TO INCREASE THE EFFICIENCY OF OIL EXTRACTION FOR MICROALGAE INDIGENOUS ISOLATES FROM POND GRESIK, EAST JAVA

The prospect of microalgae biomass as a biodiesel is as a renewable energy. The microalgae biomass is aimed to substitute the petroleum. The identification of microalgae was conducted on twice which was derived from Gresik ponds consist of 29 species. On the other hand, there were 10 species which were resulted from laboratory test of Biology, Science Faculty, UM. Among the isolated, there are 2 species that faster growth rate, Chlorella vulgaris and Spirogyra sp. Generally, extraction of oil from microalgae biomass requires a long time. The aims from the research are to examine three methods of oil extraction from the two species of microalgae, the experimental laboratory techniques. Biomass of microalgae dry powder was extracted using the solvent n- hexane by three methods, Soxhlet, maceration and ultrasonic waves. On the acquisition of microalgae oil the yield equivalent, compared with extraction time from the three methods. The smaller time of microalgae oil extraction is the more efficient extraction. The results showed: (1) the use of ultrasonic waves can improve the efficiency of microalgae oil extraction. (2) The yield of algae oil which is extracted using the method Soxhlet, maceration, and extraction with the aid of ultrasonic waves in a row is 1.58%, 1.03%, and 1.77% by the time it takes for 18 hours, 8 hours, and 2.33 hours.